Part of Body Not Responding

[GregC03]

I have a puppet where the left side of his body isn't rising up with the rest of the body.  Picture 1

This is my layout.  What am I doing wrong?

Picture 2

[David Arbor]

Is the character's Left Arm properly attached to the shoulder of the torso? Wheny you click on the arm is the green dot in the place you'd expect it to be, or is it perhaps in the center of the torso with a dotted line stretching from there to the arm layer?